Control method, system and function entity for reporting bearer event of signaling IP flow

ABSTRACT

A control method, system and function entity for reporting a bearer event of a signaling IP flow are provided. Flow identifier information such as a 5-tuple is generated for a signaling IP flow and a media IP flow so as to unify a mechanism for reporting a signaling path status and a mechanism for reporting a bearer event of a media IP flow, so that the mechanism for reporting a signaling path status is not limited by the parameter of Flow Usage, the PDP context with a signaling tag, thereby establishing corresponding PCC rules for signaling and the association between a signaling IP flow and a bearer. A method for reporting a signaling path status is further provided in the invention. In the method, for a default PDP context or a PDP context of a signaling IP flow, the predefined PCC rules are activated or signaling PCC rules generated in accordance with an Application Function address are installed, thereby an IP signaling path status is reported in accordance with rule names of the predefine PCC rules or the signaling PCC rules.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/052,487 entitled “Control Method, System and Function Entity forReporting Bearer Event of Signaling IP Flow” and filed on Mar. 20, 2008,which is a continuation of international patent application No.PCT/CN2008/070344, entitled “Control Method, System and Function Entityfor Reporting Bearer Event of Signaling IP Flow” and filed on Feb. 22,2008, which claims the benefits to Chinese patent application No.200710087199.6, entitled “Control method and function entity forreporting bearer event of signaling IP flow” and filed on Mar. 23, 2007,Chinese patent application No. 200710100495.5, entitled “Control methodand function entity for reporting bearer event of signaling IP flow” andfiled on Apr. 17, 2007, the entire contents of which are incorporatedherein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to communication technologies and inparticular to a control method, system and a function entity forreporting a bearer event of a signaling Internet Protocol (IP) flow.

BACKGROUND OF THE INVENTION

An IP Multimedia Subsystem (IMS) policy control mechanism (i.e. aService Based Local Policy (SBLP)) and a Flow Based Charging (FBC)technology are specified in Third Generation Partnership Project (3GPP)R6 protocol standards. However, the policy control involves numerousfunctions similar to those of the Flow Based Charging with respect toparticular procedures, and the separation of the policy control and theFlow Based Charging necessarily results in the increased complexity ofnetwork configuration and the increased cost, furthermore, the controlefficiency is reduced, thus influencing user experience. The standard ofthe 3GPP Release 7 converges the policy control and the Flow BasedCharging and proposes a Policy Control and Charging (PCC) architecture,as illustrated in the broken line block of FIG. 1, the architectureincludes an Online Charging System (OCS) which further includes aCustomized Applications for Mobile Network Enhanced Logic ServiceControl Point (CAMEL SCP) and a Service Data Flow Based Credit Control.

An Application Function (AF) is an application function entity such as aProxy Call Session Control Function (P-CSCF) in the IMS, and is adaptedto provide a Policy Control and Charging Rules Function (PCRF) withdynamic session information for policy establishment and chargingcontrol. The PCRF is adapted to, in accordance with application layerservice information, bearer layer information, local operatorconfiguration and a user subscription profile, provide a Policy andCharging Enforcement Function (PCEF) with QoS authorization and chargingrules and make a decision of a gating function on user plane data (forexample, disabling of gating, and discarding of an IP packet). The PCEFis typically arranged in a Gateway (GW) such as a Gateway GPRS SupportNode (GGSN) in the General Packet Radio Service (GPRS), and is adaptedto, in accordance with the policy rules sent from the PCRF, perform QoSprocessing, detect a service data flow and perform such a function asonline/offline charging. A Subscription Profile Repository (SPR) is alogical entity adapted to store and provide the user subscriptionprofile required for policy establishment and charging control for thePCRF.

With the PCC architecture, an operator may perform a control on QoS,charging, etc., of a data flow at the bearer layer, thereby enablingdetails of a transport network to be hidden from the upper servicelayer, in other words, the service layer is above a bearer controllayer, and the bearer control layer hides the details of the bearerlayer from the service layer; and perceiving the usage of resources atthe lower transport network. The PCRF, on one hand, may establish apolicy in accordance with session negotiation information indicated bythe service layer to control the usage of network resources at thebearer layer, and on the other hand, notify the service layer through areporting mechanism of a change on the usage of the underlying bearer,such as a resource loss and a gateway failure, so that the service layermay make an appropriate modification and provide a corresponding policy.

The following two terms are explained for the purpose of facilitating anunderstanding of the invention.

Flow identifier information: The flow identifier information isexpressed as a 2-tuple <a media component number (for example, a MediaComponent Number AVP), an IP flow number (for example, a Flow NumberVAP)>. The media component number identifies a media type, such as anaudio flow and a video flow. A media component may include one or moreIP flows. The flow identifier information is derived from the SessionDescription Protocol (SDP) information obtained after sessionnegotiation and uniquely identifies a media IP flow.

A 5-tuple (for example, a Flow Description AVP) consists of <a sourceaddress, a source port number, a destination address, a destination portnumber, and a protocol>. The source address and the source port numberidentify an IP address and a port number of an initiator of a session.The destination address and the destination port number identify an IPaddress and a port number of a receiver of the session. The protocolidentifies a protocol used for transport of a media IP flow. The 5-tupleidentifies uniquely a media IP flow and is adapted for associating themedia IP flow with a specific bearer during the session (which isimplemented by binding the 5-tuple with a Traffic Flow Template (TFT)identifying uniquely the bearer). The 5-tuple is derived in accordancewith the SDP for session negotiation.

In the specification of the PCC architecture, the AF subscribes to theusage of a media bearer, thus allowing a media bearer event to bereported. Upon detection of a bearer event, the PCEF reports the bearerevent to the PCRF and requests a new policy. The PCRF notifies the AF ofthe change of the bearer corresponding to an IP flow through eventreporting before establishing the new policy. The AF sends to the PCRFthe adjusted session information, based on which the PCRF establishesnew PCC rules. A specific implementation of subscribing to a mediabearer event and reporting the media bearer event is illustrated in FIG.2.

Steps S201-S206 illustrate a procedure of subscribing to a bearer eventreport and are described as follows.

Step S201. The AF sends application layer service information to thePCRF, to subscribe to a bearer event report. Session parameters such asa parameter of media component number (i.e. a Media Component NumberAVP), a parameter of flow number (i.e. a Flow Number AVP), a parameterof 5-tuple (i.e. a Flow Description AVP) and a parameter of specificaction (i.e. A Specific Action AVP) indicating a specific bearer event(such as a bearer loss and a bearer release) to be subscribed to, arecarried in an Authorize-Authenticate-Request (AAR).

Steps S202-S203. The PCRF stores the received session parameters andreturns an Authorize-Authenticate-Answer (AAA) response.

Step S204. The PCRF establishes and stores PCC rules in accordance withservice layer information, bearer layer information (provided to thePCRF by the PCEF upon a PDP context establishment request), asubscription profile and a local policy of an operator.

Steps S205-206. The PCRF sends PCC rules to the PCEF through a parameterof Charging Rule Install in a Re-Auth-Request (RAR) message, with thePPC rules being carried in the parameter of Charging Rule Install.Further, the RAR message includes PCC rule names generated for the PCCrules.

If not requested previously the PCEF to detect a bearer event, the PCRFcarries a parameter of Event Trigger for indicating a specific bearerevent to be detected, such as a bearer loss and a bearer release.

Steps S207-S211 illustrate a procedure of reporting a bearer event andare described as follows.

Step S207. A bearer event is detected by the PCEF.

Steps S208-S209. The PCEF reports the PCC rule names associated with thebearer to the PCRF, through a parameter of Charging Rule Report carryingthe PCC rule names in a Credit-Control-Request (CCR) message. During thereporting, the parameter of Event Trigger indicating the bearer event isalso carried. Upon receiving the message, the PCRF returns aCredit-Control-Answer (CCA) message to the PCEF.

Steps S210-S211. The PCRF reports to the AF an identifier of theinfluenced media IP flow along with the bearer event in accordance withthe PCC rule names reported by the PCEF. The RAR message carries aparameter of Flows which indicates identifier of the media IP flowassociated with the bearer event, and the parameter of Flows includes amedia component number and a flow number. The RAR message furthercarries a parameter of specific action indicating the specific bearerevent. Upon receiving the message, the AF returns an RAA message to thePCRF.

With the mechanism of reporting a bearer event, the bearer layer maynotify timely the service layer of the bearer event to request a newpolicy, when a bearer change such as a bearer resource loss and agateway failure occurs. The service layer perceives the bearer changewith the reporting mechanism, and responds to the bearer change, forexample, the service layer may request a session modification, a sessiontermination and the like.

Similar to a media IP flow, a signaling IP flow during a session alsoutilizes a bearer, and the service layer needs to know timely conditionsof the underlying bearer related to the signaling. When the bearerrelated to the signaling is changed, the bearer needs to report a bearerevent to the service layer, so that the service layer may make acorresponding modification timely. An existing method for reporting astatus of a signaling path is as follows.

A signaling tag is carried in a Packet Data Protocol (PDP) activationrequest by a User Equipment (UE). The PCRF perceives that a PDP contextto be established is used to bear IP signaling, and establishes andsends PCC rules to the PCEF, thereby establishing the PDP context withthe signaling tag. Upon subscribing to a signaling path status report,the AF carries a signaling IP flow tag to notify the PCRF about thesubscription to a signaling event. Upon detection of a change on thebearer with the signaling tag, the PCEF reports to the PCRF the PCC rulenames associated with the bearer, and the PCRF perceives a change of thePDP context bearing the signaling in accordance with the PCC rule names,so that the signaling path status is reported to the AS.

A specific implementation of reporting a signaling path status isillustrated in FIG. 3.

The steps S301-S307 illustrate a procedure of establishing a PDP contextwith a signaling tag and are described particularly as follows.

Step S301. The PCEF receives from a UE a PDP context activation requestcarrying a signaling tag.

Step S302. The PCEF sends a PDP context establishment request to thePCRF. The CCR message carries bearer layer information such as aparameter of Bearer Usage, which indicates that establishment of a PDPcontext with the signaling tag is requested. Optionally, the PCRFreturns a CCA message to the PCEF (not shown).

Step S303. The PCRF stores the received bearer layer information, andperceives that the PDP context to be established as requested is used tobear IMS signaling in accordance with the parameter of Bearer Usage.

Step S304. The PCRF generates PCC rules and the corresponding PCC rulenames in accordance with the bearer layer information, a subscriptionprofile and an operator policy.

Steps S305-S307. The PCRF sends the PCC rules and the corresponding PCCrule names to the PCEF, and the PCEF installs the PCC rules and returnsa response to the PDP context activation request to the UE, so that thePDP context with the signaling tag is established.

The steps S308-S312 illustrate a procedure of subscribing to a signalingpath status report and are described particularly as follows.

S308-S310. When a session message arrives at an AF, the AF initiates asubscription to a signaling path status report. Parameters of Flow Usage(set as AF signaling, which indicates a subscription related to asignaling event) and specific action (indicating a specific subscribedevent, such as a bearer loss and a bearer release) are carried in An AARmessage. The PCRF perceives that this subscription is a subscriptionrelated to a signaling patch status in accordance with the value of theparameter of Flow usage.

S311-S312. The PCRF sends the PCC rules to the PCEF. A parameter ofCharging Rule Install indicating the PCC rules is carried in an RARmessage. If detection of the bearer event by the PCEF is not subscribedto, the PCRF initiates subscription, with a parameter of Event Triggerindicating a specific bearer event being carried. The parameter of EventTrigger is generated in accordance with the parameter of specificaction.

The steps S313-S318 illustrate a procedure of reporting a signaling pathstatus and are described particularly as follows.

Step S313. A bearer event is detected by the PCEF.

Steps S314-S315. The PCEF reports the PCC rules associated with thebearer to the PCRF.

Steps S316-S318. The PCRF determines a change of a PDP channel bearingIMS signaling in accordance with the PCC rule names and reports thesignaling patch status.

The implementation of the existing mechanism for reporting a signalingpath status is dependent on the parameter of Flow Usage. Upon initiatinga subscription to a signaling path status, the service layer uses theparameter of Flow Usage as an AF signaling identifier to notify the PCRFof the signaling-related subscription. As defined currently, however,the parameter of Flow Usage exists as a sub-parameter of a parameter ofMedia Sub-Component, and the parameter of Flow Usage has to be usedalong with the parameters of Media Component Description and MediaSub-Component. For a signaling IP flow, no value of the parameter ofMedia Component Description or the parameter of Media Sub-Component isdefined in the existing standard. As a result, no signaling informationis allowed to be reported, and consequently, no mechanism for reportinga signaling path status can be implemented.

SUMMARY OF THE INVENTION

Embodiments of the invention provide a control method, a system and afunction entity for reporting a bearer event of a signaling IP flow, toimplement reporting of a signaling path status of a signaling IP flow.

To implement the solutions above, a method for reporting a bearer eventof a signaling IP flow is provided according to an embodiment of theinvention, and the method includes:

sending, by an Application Function, a request for subscribing to abearer event of a signaling IP flow to a Policy Control and ChargingRules Function, where the request carries flow identifier informationsuch as a 5-tuple and/or other flow identifier information of thesignaling IP flow; and

receiving, by the Application Function, a bearer event report of thesignaling IP flow from the Policy Control and Charging Rules Function,where the bearer event report carries the flow identifier informationsuch as the 5-tuple and/or other flow identifier information of thesignaling IP flow.

An Application Function is provided according to another embodiment ofthe invention, and the Application Function includes:

a first subscription request sending unit adapted to send a request forsubscribing to a bearer event of a signaling IP flow to a Policy Controland Charging Rules Function, where the subscription request carries flowidentifier information such as a 5-tuple and/or other flow identifierinformation of the signaling IP flow; and

a first bearer event report receiving unit adapted to receive a bearerevent report of the signaling IP flow from the Policy Control andCharging Rules Function, where the bearer event report carries the flowidentifier information such as the 5-tuple and/or the other flowidentifier information of the signaling IP flow.

An Policy Control and Charging Rules Function is provided according toanother embodiment of the invention, which includes:

a first subscription request receiving unit adapted to receive a requestfor subscribing to a bearer event of a signaling IP flow from anApplication Function, where the subscription request carries a flowidentifier information such as 5-tuple and/or other flow identifierinformation of the signaling IP flow; and

a first bearer report processing unit adapted to generate and send abearer event report carrying information including Policy Control andCharging rules names associated with the bearer event corresponding tothe flow identifier information such as the 5-tuple and/or the otherflow identifier information of the signaling IP flow.

A system for reporting a bearer event of a signaling IP flow is providedaccording to another embodiment of the invention, and the systemincludes an Application Function and a Policy Control and Charging RulesFunction:

The Application Function includes:

a first subscription request sending unit adapted to send a request forsubscribing to a bearer event of a signaling IP flow to a Policy Controland Charging Rules Function, where the subscription request carries flowidentifier information such as a 5-tuple and/or other flow identifierinformation of the signaling IP flow; and

a first bearer event report receiving unit adapted to receive a bearerevent report of the signaling IP flow sent by the Policy Control andCharging Rules Function, where the bearer event report carries the flowidentifier information such as the 5-tuple and/or the other flowidentifier information of the signaling IP flow.

The Policy Control and Charging Rules Function includes:

a first subscription request receiving unit adapted to receive from thefirst subscription request sending unit the request for subscribing tothe bearer event of the signaling IP flow, where the subscriptionrequest carries flow identifier information such as a 5-tuple and/or theflow identifier information of the signaling IP flow; and

a first bearer report processing unit adapted to generate and send thebearer event report carrying information including Policy Control andCharging rule names associated with the bearer event corresponding tothe flow identifier information such as the 5-tuple and/or the otherflow identifier information of the signaling IP flow.

With the control method, system and function entity for reporting abearer event of an IP flow provided according to the embodiments of theinvention, flow identifier information such as a 5-tuple is generatedfor a signaling IP flow and a media IP flow respectively, so that themechanism for reporting a signaling path status is not limited by theparameter of Flow Usage, the PDP context with a signaling tag, etc.,thereby reporting the signaling path status of a signaling IP flow andunifying a mechanism for reporting a signaling path status and amechanism for reporting a bearer event of a media IP flow, and furtherestablishing corresponding PCC rules for signaling and the associationbetween an signaling IP flow and a bearer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a configuration of the PCC architecturein the prior art;

FIG. 2 is a schematic flowchart of a mechanism for subscribing to andreporting a media bearer event in the prior art;

FIG. 3 is a schematic flowchart of a mechanism for reporting a signalingpath status in the prior art;

FIGS. 4 and 5 each are a schematic flowchart of a control method forreporting a bearer event of a signaling IP flow according to anembodiment of the invention;

FIGS. 6 and 7 each are a schematic diagram of a general configuration ofa control system for reporting a bearer event of a signaling IP flowaccording to an embodiment of the invention;

FIGS. 8, 9 and 10 each are a schematic flowchart of a method forreporting a signaling IP flow path status according to an embodiment ofthe invention; and

FIGS. 11 and 12 each are a schematic diagram of a general configurationof a PCRF according to an embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With insight into the existing mechanism for reporting a media bearerevent and the mechanism for reporting a signaling path status in theBackground of the Invention, it can be seen that an application scenarioof the existing mechanism for reporting a signaling path status islimited in numerous aspects as follows.

An implementation of the existing mechanism for reporting a signalingpath status is dependent upon the parameter of Flow Usage. Uponinitiating a subscription to a signaling path status, the service layeruses the parameter of Flow Usage as an AF signaling identifier to notifythe PCRF of the signaling-related subscription. As defined currently,however, the parameter of Flow Usage exists as a sub-parameter of aparameter of Media Sub-Component, and the parameter of Flow Usage has tobe used along with the parameters of Media Component Description andMedia Sub-Component. For a signaling IP flow, no value of the parameterof Media Component Description or the parameter of Media Sub-Componentis defined in the existing standard, as a result, no signalinginformation is allowed to be sent or reported, and consequently, nomechanism for reporting a signaling path status can be implemented.

An implementation of the existing mechanism for reporting a signalingpath status is also dependent upon establishment of a PDP context with asignaling tag, and an application scenario in which a signaling-bearingPDP context without signaling tag is not supported. A signaling tagneeds to be carried during establishment of the PDP context, so that thePCRF may perceive which PDP channel is used to bear signaling. When thebearer is changed subsequently, the PCRF may determine that thesignaling-bearing PDP context is changed in accordance with PCC rulenames corresponding to the bearer, thereby implementing reporting of asignaling path. However, the establishment of a PDP context with asignaling tag relies on the support by UE capabilities and the operator.In other words, an application scenario where a PDP context which bearssignaling is without signaling tag may be present among practicalnetwork applications. Consequently, no mechanism for reporting asignaling path status can be implemented in the application scenariowhere a PDP context is provided with no signaling tag.

An implementation of the existing mechanism for reporting a signalingpath status is also dependent upon associated PCC rules generated duringestablishment of a PDP context. If no associated PCC rule is generatedduring establishment of the PDP context which bears signaling, theaddress and port information of a signaling IP flow at the service layercan not be sent to the PCRF during a session in accordance with theexisting mechanism, and consequently no signaling-related PCC rule canbe established, as a result, the PCEF can not report any bearer event tothe PCRF and no signaling path status reporting can be implemented.

Furthermore, the existing mechanism for reporting a signaling pathstatus is independent of the mechanism for reporting a media bearerevent, as a result, the entire mechanism for reporting a bearer event iscomplex. Furthermore, in the mechanism for reporting a signaling pathstatus, no 5-tuple for signaling IP flow that is corresponding to asignaling IP flow at the service layer is generated, consequently noassociation between the signaling IP flow and a bearer can beestablished.

In view of the drawbacks present in the existing mechanism for reportinga signaling path status, according to an embodiment of the invention,there is provided a control method for reporting a signaling path statusof a signaling IP flow, and the method combines a mechanism forreporting a signaling path status and a mechanism for reporting a mediabearer status, so that a bearer reporting mechanism is simplified, andan application of the mechanism for reporting a signaling path status isnot limited by, for example, the parameter of Flow Usage, provision of asignaling tag for a PDP context and the necessity of generatingassociated PCC rules during establishment of a PDP context.

In an embodiment of the invention, the control method for reporting abearer event includes the following steps.

1. For each IP flow for which a request for a subscription to a bearerevent report is triggered, an AF generates flow identifier informationsuch as a 5-tuple, and generates flow identifier information inaccordance with the type of the IP flow. The IP flow may include asignaling IP flow and a media IP flow, and both the flow identifierinformation such as the 5-tuple and/or the other flow identifierinformation may identify the IP flow and the type of the IP flow.

2. The AF sends to a PCRF the request for subscribing to a bearer eventof the IP flow. The subscription request carries the flow identifierinformation (such as 5-tuple and the other flow identifier information).

3. The PCRF establishes PCC rule information including PCC rules and PCCrule names that is associated with the bearer of the IP flow, stores thePCC rule names and the flow identifier information correspondingly, andsends the PCC rule information to a PCEF.

In some application scenarios, the associated PCC rule information isalready established for the IP flow bearer and sent to the PCEF duringnegotiation of a PDP context or a session. In this case, there isalready PPC rule information available for the IP flow, and the PCRFneed not establish and send any PCC rule information associated with theIP flow bearer, but stores the generated PCC rule names and flowidentifier information.

4. The PCEF installs the PCC rule, and upon detection of a bearer event,reports the PCC rule names and the detected bearer event to the PCRF.

5. The PCRF obtains the flow identifier information in accordance withthe associated PCC rule names, and the obtained flow identifierinformation is sent to the AF in a bearer event report.

6. The AF determines the type of the received bearer event report inaccordance with the information carried in the bearer event report,where the type of a bearer event report of the signaling IP flow is asignaling path status report and the type of a bearer event report of amedia IP flow is a media bearer event report.

In step 5, flow identifier information such as a corresponding 5-tuplemay also be carried in the bearer event report and transmitted to theAF, and in step 6, the AF determines the type of the received bearerevent report in accordance with the flow identifier information (such asthe 5-tuple).

In the embodiment of the invention, the mechanism for reporting asignaling path status and the mechanism for reporting a bearer event ofa media IP flow is unified, and signaling information is sent by theservice layer, so that the mechanism for reporting a signaling pathstatus is not limited by the parameter of Flow Usage, provision of asignaling tag for a PDP context and the like, thus establishing forsignaling IP flow a PCC rule and the association between an signaling IPflow and a bearer.

In an embodiment of the invention, the AF need not notify the PCRF thatwhether a signaling IP flow or a media IP flow is involved upon sendingservice information to the PCRF, thus hiding the flow type from beingperceived by the PCRF. Upon detection of a subscribed bearer event, thePCEF reports PCC rule names related to the bearer to the PCRF, and thePCRF determines flow identifier information in accordance with the PCCrule names and reports the flow identifier information and the bearerevent to the AF. The AF determines the type of the bearer event reportin accordance with a generation rule of the flow identifier information,and responds appropriately.

In a further embodiment of the invention, the mechanism for reporting abearer event is independent of the type of an established PDP context.The AF at the service layer plane generates flow identifier informationsuch as a 5-tuple for a signaling IP flow and a media IP flow inaccordance with a uniform rule, and indicates the specific flowidentifier information (such as a 5-tuple) when subscribing to a bearerevent corresponding to a flow from the PCRF. The PCRF establishes theassociation between the bearer and the PCC rule in accordance with theflow identifier information (such as the above-referenced 5-tuple) andsends the association to the PCRF. When a bearer event occurs, the PCEFreports the PCC rule names associated with the bearer and the bearerevent.

In yet a further embodiment of the invention, flow identifierinformation such as 5-tuple and/or other flow identifier information maybe generated as follows: the flow identifier information such as a5-tuple and/or other flow identifier information of a media IP flow isderived from the SDP for session negotiation. The flow identifierinformation (such as 5-tuple) of a signaling IP flow is generated inaccordance with information in a SIP message, such as a source IPaddress, a destination IP address, a port number and a protocol adopted.With reference to a media component number of a media IP flow, which isstarted from 1 and used for identifying in an ascending order, asignaling IP flow may be provided with a default media component number0, for example, <0, 1> is used to indicate a signaling IP flow.

With reference to FIG. 4, a method for reporting a signaling path statusaccording to an embodiment of the invention is shown. The control methodaccording to the embodiment of the invention is independent of PDPcontext establishment. A subscription procedure and a reportingprocedure are shown in FIG. 4, where the steps S401-S409 illustrate asubscription procedure and are described as follows.

Step S401. An AF initiates a subscription to a signaling path statusupon receiving a trigger for the subscription, for example, when aregistration message arrives at the AF and the AF is required tosubscribe to a signaling path status, or during session negotiation.

Step S402. For unification of the mechanism for reporting a media bearerevent and the mechanism for reporting a signaling path status, uponsubscribing to a bearer event corresponding to a signaling IP flow, theAF generates a signaling IP flow such as a 5-tuple and/or other flowidentifier information for the signaling IP flow, and flow identifierinformation (a media component number and a flow number) and thesignaling IP flow 5-tuple as well as the specific subscribed bearerevent indicated by the parameter of specific action are carried in theAAR.

Steps S403-S404. The PCRF stores the received service layer informationand returns an AAA to the AF.

Step S405. The PCRF establishes and stores PCC rule information of thesignaling IP flow in accordance with the received service layerinformation (the signaling IP flow (such as 5-tuple), QoS information,etc.), bearer information (provided by the PCEF during PDPestablishment), a subscription profile and an operator policy, where thePCC rule information includes PCC rules and the corresponding PCC rulenames. Further, if the PCRF determines that there exist already PCCrules and PCC rule names available for the signaling IP flow, the PCRFsends the PCC rules and the PCC rule names to the PCEF.

Step S406. The PCRF sends to the PCEF an RAR message which carries thePCC rule information in a parameter of Charging Rule Install.

If the PCRF has subscribed previously to a bearer event reportingprocedure from the PCEF, the PCRF need not initiate again anysubscription from the PCEF; otherwise, the PCRF need initiate asubscription to a bearer event from the PCEF. As illustrated in FIG. 4,the subscription to a bearer event and the sending of the PCC ruleinformation may be performed together through the same RAR message, andin the RAR message, the parameter of Event Trigger corresponding to theparameter of specific action is carried for specifying the bearer eventto which the subscription from the PCEF is made.

Steps S407-S408. The PCEF installs the PCC rule information and returnsan AAA to the PCRF.

In the above subscription procedure, the AF subscribes to a bearer eventreport of the signaling IP flow with the use of the generated flowidentifier information such as 5-tuple and flow identifier informationof the signaling IP flow, so that the service layer can initiate asubscription to a signaling path status independently of the parameterof Flow Usage.

Further, the PCRF establishes and stores the PCC rule information inaccordance with the received service layer information (flow identifierinformation such as the 5-tuple of the signaling IP flow, the QoSinformation, etc.), the bearer information (provided by the PCEF duringPDP establishment), the subscription profile and the operator policy,thereby ensuring that a PDP context of each signaling IP flow isassociated with PCC rules. Practically, if the PCRF established andstored previously the PCC rule information, the PCRF sends directly theestablished PCC rule information to the PCEF. Upon detection of thebearer event subscribed to by the PCRF, the PCEF reports the PCC rulenames associated with the detected bearer event and the detected bearerevent to the PCRF. In other words, if there is PCC rule informationavailable for the signaling IP flow, no establishment or storage of PCCrule information needs to be performed in the present step, but the PCCrule names and the 5-tuple of the IP flow need to be associated andstored.

Steps S409-S413 illustrate a procedure of reporting a bearer event andare described particularly as follows.

Step S409. The PCEF detects an event related to the bearer.

Steps S410-S411. Upon detection of the event related to the bearer, thePCEF reports the PCC rule names associated with the bearer to the PCRF.

Steps S412-S413. In accordance with the PCC rule names, the PCRF reportsto the AF about the corresponding flow identifier information along withthe bearer event via a bearer event report, and the AF returns an RAAresponse to the PCRF upon the receipt of the report.

Furthermore, the AF determines the type of the IP flow associated withthe reported bearer event in accordance with the flow identifierinformation in the bearer event report. If the flow identifierinformation indicates a signaling IP flow, a signaling path statusreport is determined; otherwise a media bearer event report isdetermined.

In the procedure of reporting an event related to the bearer, the PCEFand the PCRF need not distinguish an IP flow type, thereby unifying thereporting mechanisms and associating the signaling IP flow and thebearer event.

With reference to FIG. 5, another embodiment of the invention isillustrated. The function of the flow identifier information to identifyuniquely an IP flow may be implemented by a 5-tuple.

Step S502. The AF may not issue any flow identifier information uponsubscribing to a bearer event corresponding to an IP flow.

Step S512. The PCRF reports a 5-tuple of the signaling IP flow alongwith the bearer event to the AF in accordance with PCC rule names, andthe AF returns an RAA response to the PCRF.

The AF determines the type of the IP flow associated with the reportedbearer event in accordance with flow identifier informationcorresponding to the 5-tuple. If the flow identifier informationcorresponds to a signaling IP flow, a signaling path status report isdetermined; otherwise, a media bearer event report is determined.

The other steps are the same as those in the flow illustrated in FIG. 4,and descriptions thereof are not stated again.

According to an embodiment of the invention, after defining flowidentifier information such as a 5-tuple and values of a media componentnumber and a flow number for a signaling IP flow, signaling informationmay be sent from the service layer, so that the subscription andreporting procedure may be embodied.

In an embodiment of the invention, flow identifier information such as a5-tuple is generated consistently for a signaling IP flow and a media IPflow, so that during a session, PCC rules may be established for thesignaling IP flow and the signaling IP flow may be bound to a bearer.Thus, a signaling path status can be reported without any limitation ofa PDP type.

In an embodiment of the invention, service layer signaling informationmay be sent to establish PCC rules corresponding to the signaling inreal time, thereby establishing the association between a signaling IPflow and a bearer.

In a further embodiment of the invention, to subscribe to a bearerevent, the PCRF need not be notified about the signaling-relatedsubscription; and upon detection of the bearer event, the PCRF need notperceive whether the related subscription is a signaling-relatedsubscription or a media-related subscription, but reports the 5-tuple orflow identifier information corresponding to the bearer to the AF. TheAF checks whether the report relates to reporting of a media bearerevent or a signaling path status. In other words, the flow type isperceived by the AF instead of the PCRF, so that the mechanism forreporting a signaling path status and the mechanism for reporting amedia bearer event are unified.

As can be seen from the above, a universal, simple and efficient controlmethod for reporting a bearer event is provided according to theembodiment of the invention, and the mechanism for reporting a signalingpath status and the mechanism for reporting a media event of a media IPflow are unified, thereby improving the mechanism for reporting asignaling path status and ensuring implementation of a signaling pathstatus report.

As illustrated in FIG. 6, a control system for implementing the controlmethod illustrated in FIG. 4 according to a further embodiment of theinvention is shown, and the control system includes an AF 61, a PCRF 62and a PCEF 63. The embodiment is illustrated by way of an example inwhich flow identifier information such as a 5-tuple of an IP flow iscarried, but the invention is not limited to this. For example, a5-tuple or both a 5-tuple and flow identifier information may becarried. The AF 61 includes:

a first subscription request sending unit 611 adapted to send a requestfor subscribing to a bearer event of a signaling IP flow from the PolicyControl and Charging Rules Function, where the subscription requestcarries flow identifier information such as a 5-tuple of the signalingIP flow; and

a first bearer event report receiving unit 612 adapted to receive abearer event report of the signaling IP flow from the Policy Control andCharging Rules Function, where the bearer event report carries flowidentifier information (such as the 5-tuple) of the signaling IP flow.

The PCRF 62 primarily includes a first subscription request receivingunit 621 and a first bearer report processing unit 624 and preferably afirst rule establishing unit 622 and a first bearer event receiving unit623.

The first subscription request receiving unit 621 is adapted to receivethe request for subscribing to the bearer event of the signaling IP flowfrom an Application Function. The subscription request includes the5-tuple of the signaling IP flow.

The first rule establishing unit 622 is adapted to establish PolicyControl and Charging rules and names of the Policy Control and Chargingrules corresponding to the signaling IP flow in accordance with flowidentifier information (such as the 5-tuple) of the signaling IP flow,and send the PCC rules and the PCC rule names to the Policy and ChargingEnforcement Function.

The first bearer event receiving unit 623 is adapted to receive thedetected bearer event and the Policy Control and Charging rule namesassociated with the detected bearer event from the Policy and ChargingEnforcement Function.

The first bearer report processing unit 624 is adapted to generate andsend a bearer event report carrying the flow control information of thesignaling IP flow. The flow control information may be the 5-tuple ofthe signaling IP flow corresponding to the Policy Control and Chargingrule names associated with the bearer event.

Preferably, the PCRF 62 further includes a determination unit (notshown) adapted to instruct the first rule establishing unit to establishPolicy Control and Charging rules and names of the Policy Control andCharging rules corresponding to the IP flow, upon determining that noPolicy Control and Charging rule or Policy Control and Charging rulename is available for the signaling IP flow carried in the subscriptionrequest; or upon determining that there exist Policy Control andCharging rules and Policy Control and Charging rule names available forthe signaling IP flow carried in the subscription request, send thecharging rules and the charging rule names to the Policy and ChargingEnforcement Function.

According to an embodiment of the invention, there is further providedan Application Function including a first subscription request sendingunit and a first bearer event report receiving unit. The firstsubscription request sending unit is adapted to send a request forsubscribing to a bearer event of a signaling IP flow to a Policy Controland Charging Rules Function, and the subscription request carries a5-tuple and/or flow identifier information of the signaling IP flow; andthe first bearer event report receiving unit is adapted to receive abearer event report of the signaling IP flow from the Policy Control andCharging Rules Function, and the bearer event report carries the 5-tupleand/or the flow identifier information of the signaling IP flow.

The implementation of the Application Function is the same as that inthe above method and system and descriptions thereof are not givenherein again.

According to another embodiment of the invention, there is provided aPolicy Control and Charging Rules Function including a firstsubscription request receiving unit and a first bearer report processingunit. The first subscription request receiving unit is adapted toreceive a request for subscribing to a bearer event of a signaling IPflow from an Application Function, and the subscription request carriesflow identifier information such as a 5-tuple and/or ther flowidentifier information of the signaling IP flow; and the first bearerreport processing unit is adapted to generate and return a bearer eventreport carrying such information as Policy Control and Charging rulenames associated with the bearer event corresponding to the 5-tupleand/or the other flow identifier information of the signaling IP flow.

Preferably, the Policy Control and Charging Rules Function may furtherinclude:

a first rule establishing unit adapted to establish the Policy Controland Charging rules and the Policy Control and Charging rule namescorresponding to the signaling IP flow in accordance with flowidentifier information such as a 5-tuple and/or other flow identifierinformation of the signaling IP flow, and send the Policy Control andCharging rules and the Policy Control and Charging rule names to aPolicy and Charging Enforcement Function; and

a first bearer event receiving unit adapted to receive the detectedbearer event and the Policy Control and Charging rule names associatedwith the detect bearer event from the Policy and Charging EnforcementFunction.

Preferably, the Policy Control and Charging Rules Function may furtherinclude:

a determination unit adapted to instruct the first rule establishingunit to establish Policy Control and Charging rules and Policy Controland Charging rule names corresponding to the IP flow, upon determiningthat no Policy Control and Charging rule or Policy Control and Chargingrule name is available for the signaling IP flow carried in thesubscription request; or upon determining that there exist PolicyControl and Charging rules and Policy Control and Charging rule namesavailable for the signaling IP flow carried in the subscription request,send the charging rules and the charging rule names to the Policy andCharging Enforcement Function.

The implementation of the Application Function is the same as that inthe above method and system and descriptions thereof are not givenherein again.

With reference to FIG. 7, a control system for implementing the controlmethod illustrated in FIG. 5 is provided according to yet anotherembodiment of the invention, and the control system includes an AF 71, aPCRF 72 and a PCEF 73, and the AF 71 primarily includes:

a second subscription request sending unit 711 adapted to send a requestfor subscribing to a bearer event of a signaling IP flow to the PolicyControl and Charging Rules Function, where the subscription requestcarries flow identifier information such as a 5-tuple of the signalingIP flow and flow identifier information of the signaling IP flow (thisembodiment is illustratively described with, but not limited to the5-tuple of the signaling IP flow and the flow identifier information ofthe signaling IP flow); and

a second bearer event report receiving unit 712 adapted to receive abearer event report of the signaling IP flow from the Policy Control andCharging Rules Function, where the bearer event report carries the flowidentifier information of the signaling IP flow.

The PCRF 72 primarily includes:

a second subscription request receiving unit 721 adapted to receive therequest for subscribing to the bearer event of the signaling IP flowfrom the Application Function, where the subscription request carriesthe flow identifier information (such as 5-tuple) of the signaling IPflow and the flow identifier information of the signaling IP flow;

a second rule establishing unit 722 adapted to establish Policy Controland Charging rules and Policy Control and Charging rule namescorresponding to the signaling IP flow in accordance with the flowidentifier information (such as 5-tuple) of the signaling IP flow, andsend the Policy Control and Charging rules and Policy Control andCharging rule names to the Policy and Charging Enforcement Function(optionally);

a second bearer event receiving unit 723 adapted to receive the detectedbearer event and the Policy Control and Charging rule names associatedwith the detected bearer event from the Policy and Charging EnforcementFunction (optionally); and

a second bearer report processing unit 724 adapted to generate and sendthe bearer event report carrying the flow identifier information of thesignaling IP flow, where the identifier information may be the flowidentifier information of the signaling IP flow corresponding to thePolicy Control and Charging rule names associated with the bearer event.

A method for reporting a signaling IP flow path status is providedaccording to yet another embodiment of the invention. In the method, fora request of activating the first default PDP context from an IPConnectivity Access Network (IP-CAN) session, PCC rules are activated orinstalled in advance for the default PDP context; if the IP-CAN sessionrequests again establishing a dedicated PDP context for a signaling IPflow, the previous PCC rules for the default PDP context are deactivatedor deleted and PCC rules are activated or installed for the PDP contextof the signaling IP flow, and thus an IP signaling path status report istriggered in accordance with rule names of the PCC rules newly activatedor installed for the PDP context of the signaling IP flow; otherwise ifthe default PDP context is used to bear the signaling IP flow, an IPsignaling path status report may be triggered in accordance with rulenames of the PCC rules activated or installed in advance for the defaultPDP context.

The PCC rules activated or installed in advance for the default PDPcontext and the PCC rules newly activated or installed for the PDPcontext of the signaling IP flow may be generated in the followingmethods.

1. A Predefinition Method

Predefined PCC rules are arranged in the PCEF for the signaling IP flow.Upon each receipt of a request for activating the default PDP context ora request for activating the PDP context of the signaling IP flow, thePCRF activates the predefined PCC rules for the PDP context. In thismethod, the predefined PCC rules and names thereof are fixed, and theaddress of an AF for processing IP signaling, which is included in thepredefined PCC rules is also fixed. If the address of the AF forprocessing IP signaling is modified, predefined PCC rules areregenerated and updated in synchronization to the PCEF and the PCRF.

2. A Dynamic Generation Method

The PCRF is preconfigured with the address of the AF for processing IPsignaling. Upon each receipt of a request for activating the default PDPcontext or a request for activating the PDP context of the signaling IPflow, the PCRF generates signaling PCC rules including the preconfiguredaddress of the AF for processing IP signaling and sends the signalingPCC rules to the PCEF for installing.

The above two methods may be used in combination or separately, anddetailed descriptions thereof will be presented below in an embodimentwith reference to the drawings.

With reference to FIG. 8, a mechanism for reporting a signaling IP flowpath status in the first predefinition method in which PCC rules arepredefined is shown, where the PCEF is configured with the predefinedPCC rules and the PCRF is configured with names of the predefined PCCrules, and a specific flow of the mechanism includes the following.

Steps S801-S805 illustrate a procedure of activating a default PDPcontext and activating the predefined PCC rules for the default PDPcontext, and are described particularly as follows.

Step S801. The PCEF receives a request for activating the default PDPcontext from a UE.

Step S802. The PCEF sends to the PCRF a CCR message including identifierinformation of the default PDP context.

Step S803. Via a CCA message, the PCRF instructs the PCEF to activatethe predefined PCC rules for the default PDP context, where the CCAmessage includes the identifier information of the fault PDP context andthe predefined PCC rule names.

Step S804. The PCEF receives the CCA message and activates thepredefined PCC rules for the default PDP context.

Step S805. The PCEF returns a default PDP context activation response tothe UE.

Thereafter, the user may initiate a request for activating a dedicatedPDP context of a signaling IP flow. Steps S806-S810 illustrate aprocedure of establishing a PDP context of a signaling IP flow,deactivating the predefined PCC rules for the default PDP context andactivating predefined PCC rules for the PDP context of the signaling IPflow, and are described particularly as follows.

Step S806. The PCEF receives a request for activating a PDP context fromthe UE, where the request carries a signaling tag.

Step S807. The PCEF sends to the PCRF a CCR message including theparameter of Bearer Usage and an identifier of the PDP context of thesignaling IP flow, where the parameter of Bearer Usage includessignaling tag information.

Step S808. The PCRF perceives that the PDP context to be established isused to bear signaling in accordance with the signaling tag informationin the parameter of Bearer Usage, and instructs, via a CCA message, thePCEF to deactivate the predefined PCC rules for the default PDP contextand activate predefined PCC rules for the PDP context of the signalingIP flow, where the CCA message includes: the identifier of the PDPcontext of the signaling IP flow and predefined PCC rule names; and theidentifier of the default PDP context and predefined PCC rule names.

Step S809. The PCEF receives the CCA message, deactivates the predefinedPCC rules for the default PDP context and activates the predefined PCCrules for the PDP context of the signaling IP flow.

Step S810. The PCEF returns a signaling IP flow PDP context activationresponse to the UE.

Steps S811-S816 illustrate a procedure of subscribing to a signaling IPflow path status report and reporting the signaling IP flow path status,and are described particularly as follows.

Step S811. The AF processes SIP signaling from the UE.

Step S812. The AF subscribes to a signaling IP flow path status from thePCRF.

Step S813. The PCRF subscribes to an event related to the bearer of thePDP context from the PCEF.

Step S814. A bearer event of the PDP context corresponding to thepredefined PCC rules is detected by the PCEF.

Step S815. The PCEF sends to the PCRF a PDP bearer event detectionreport carrying the corresponding bearer event and the predefined PCCrule names.

Step S816. The PCRF sends a signaling IP flow signaling path statusreport to the AF.

Therefore, if the UE initiates subsequently no request for activatingthe PDP context of the signaling IP flow, session signaling is borne inthe default PDP context, and the mechanism for reporting a signaling IPflow path status is implemented by the predefined PCC rules and thepredefined PCC rule names for the default PDP context; if a request foractivating the PDP context of the signaling IP flow is initiated, thesession signaling is borne in the dedicated PDP context of the signalingIP flow, and the mechanism for reporting a signaling IP flow path statusis implemented by the predefined PCC rules and the predefined PCC rulenames for the PDP context of the signaling IP flow.

With reference to FIG. 9, a mechanism for generating signaling PCC rulesand names thereof and reporting a signaling IP flow path status in thesecond method is illustrated, in the mechanism, the PCRF is configuredwith an address of an AF for processing SIP signaling for the UE, and aspecific flow of the mechanism includes the following.

Steps S901-S906 illustrate a procedure of establishing the default PDPcontext and installing the signaling PCC rules and names thereof for thedefault PDP context, and are described as follows.

Step S901. The PCEF receives a request for activating the default PDPcontext sent from the UE.

Step S902. The PCEF sends to the PCRF a CCR message including identifierinformation of the default PDP context.

Step S903. The PCRF generates signaling PCC rules including the addressof the AF.

Step S904. Via a CCA message, the PCRF instructs the PCEF to install thesignaling PCC rules for the default PDP context, where the CCA messageincludes the identifier information of the default PDP context and thesignaling PCC rules.

Step S905. The PCEF receives the CCA message and installs the signalingPCC rules for the default PDP context.

Step S906. The PCEF returns a default PDP context activation response tothe UE.

Thereafter, the user may initiate a request for activating the dedicatedPDP context of the signaling IP flow. Steps S907-S912 illustrate aprocedure of activating the PDP context of the signaling IP flow,deleting the signaling PCC rules for the default PDP context andinstalling signaling PCC rules for the PDP context of the signaling IPflow, and are described particularly as follows.

Step S907. The PCEF receives a request for activating a PDP context fromthe UE, where the request carries a signaling tag.

Step S908. The PCEF sends to the PCRF a CCR message including theparameter of Bearer Usage and an identifier of the PDP context of thesignaling IP flow.

Step S909. The PCRF perceives that the PDP to be established is used tobear signaling in accordance with the parameter of Bearer Usage, andgenerates signaling PCC rules including the address of the AF.

Step S910. Via a CCA message, the PCRF instructs the PCEF to delete thesignaling PCC rules for the default PDP context and install thesignaling PCC rules for the PDP context of the signaling IP flow, wherethe CCA message includes: the identifier of the PDP context of thesignaling IP flow and the signaling PCC rules; and the identifier of thedefault PDP context and the signaling PCC rules.

Step S911. The PCEF receives the CCA message, deletes the signaling PCCrules for the default PDP context and installs the signaling PCC rulesfor the PDP context of the signaling IP flow.

Step S912. The PCEF returns a signaling IP flow PDP context activationresponse to the UE.

Steps S913-S918 illustrate a procedure of subscribing to a signaling IPflow path status report and reporting the signaling IP flow path status,in which the PCEF sends a bearer event detection report of the PDPcontext corresponding to the signaling PCC rules, and the PCRF sends asignaling IP flow path status report in accordance with the signalingPCC rule names carried in the report.

Therefore, if the UE initiates subsequently no request for activatingthe PDP context of the signaling IP flow, session signaling is borne inthe default PDP context, and the mechanism for reporting a signaling IPflow path status is implemented by the signaling PCC rules and thesignaling PCC rule names for the default PDP context; if a request foractivating the PDP context of the signaling IP flow is initiated, thesession signaling is borne in the dedicated PDP context of the signalingIP flow, and the mechanism for reporting a signaling IP flow path statusis implemented by the signaling PCC rules and the signaling PCC rulenames for the PDP context of the signaling IP flow.

In the step S908, if the CCR message sent from the PCEF to the PCRFfurther includes a Traffic Flow Template (TFT) of the PDP context, thePCRF may also compare address in the TFT with the address of the AF inthe step S909, and if the address in the TFT matches the address of theAF, the PCRF may perceive that the PDP to be established is used to bearsignaling, and generate signaling PCC rules including the address of theAF. In other words, in the step S909, if the PCRF can not perceive thatthe PDP to be established is used to bear signaling in accordance withthe parameter of Bearer Usage, the PCRF may further perceive that thePDP to be established is used to bear signaling in accordance with theTFT. Alternatively, the PCRF may perceive that the PDP to be establishedis used to bear signaling in accordance with the TFT directly, andgenerate signaling PCC rules including the address of the AF.

As illustrated in FIG. 10, the predefined PCC rules are activated in thedefault PDP context and the generated signaling PCC rules are installedin the dedicated PDP context of the signaling IP flow. In thisembodiment, the PCEF is configured with the predefined PCC rules and thenames thereof, and the PCRF is configured with the predefined PCC rulenames and the address of the AF for processing SIP signaling for the UE.

Step S1008. The PCRF perceives that the PDP to be established is used tobear signaling in accordance with the parameter of Bearer Usage or theaddress information in the TFT, and generates signaling PCC rulesincluding the address of the AF.

Step S1009. Through a CCA message, the PCRF instructs the PCEF todeactivate the predefined PCC rules for the default PDP context andinstall the signaling PCC rules for the PDP context of the signaling IPflow, where the CCA message includes: the identifier of the PDP contextof the signaling IP flow and the signaling PCC rules; and the identifierof the default PDP context and the predefined PCC rule names.

Step S1010. The PCEF receives the CCA message, deactivates thepredefined PCC rules for the default PDP context and installs thesignaling PCC rules for the PDP context of the signaling IP flow.

Descriptions of the other steps are not given again. Therefore, if theUE initiates subsequently no request for activating the PDP context ofthe signaling IP flow, session signaling is borne in the default PDPcontext, and the mechanism for reporting a signaling IP flow path statusis implemented by the predefined PCC rules and the predefined PCC rulenames for the default PDP context; if a request for activating the PDPcontext of the signaling IP flow is initiated, the session signaling isborne in the dedicated PDP of the signaling IP flow, and the mechanismfor reporting a signaling IP flow path status is implemented by thesignaling PCC rules and the names thereof for the PDP context of thesignaling IP flow.

Practically, the generated signaling PCC rules and the names thereof maybe installed in the default PDP context, and the predefined PCC rulesmay be activated in the dedicated PDP context of the signaling IP flow,and in this embodiment, the PCEF needs to be configured with thepredefined PCC rules and the names thereof, and the PCRF needs to beconfigured with the predefined PCC rule names and the address of the AFfor processing SIP signaling for the UE. In this case, if the UEinitiates subsequently no request for activating the PDP context of thesignaling IP flow, the session signaling is borne in the default PDPcontext, and the mechanism for reporting a signaling IP flow path statusis implemented by the signaling PCC rules and the names thereofinstalled in the default PDP context; and if a request for activatingthe PDP context of the signaling IP flow is initiated, the sessionsignaling is borne in the dedicated PDP context of the signaling IPflow, and the mechanism for reporting a signaling IP flow path status isimplemented by the predefined PCC rules and the names thereof activatedin the PDP context of the signaling IP flow.

As shown in FIG. 11, a PCRF is provided according to yet anotherembodiment of the invention, and the PCRF includes:

a first storage unit 111 adapted to store the predefined PCC rules andthe names thereof;

a first association unit 112 adapted to activate the predefined PCCrules and the names thereof for a PDP context to be activated asrequested;

a first notification unit 113 adapted to instruct a PCEF to activate thepredefined PCC rules for the PDP context; and

a first reporting unit 114 adapted to receive a PDP bearer eventdetection report carrying the predefined PCC rule names, and send asignaling IP flow path status report to an Application Function.

As shown in FIG. 12, a PCRF is provided according to another embodimentof the invention, and the PCRF includes:

a second storage unit 121 adapted to store a preconfigured address of anAF;

a second association unit 122 adapted to generate signaling PCC rulesincluding the address of the AF and names of the signaling PCC rules,and activate the signaling PCC rules and the names thereof for a PDPcontext to be activated as requested;

a second notification unit 123 adapted to instruct a PCEF to install thesignaling PCC rules for the PDP context; and

a second reporting unit 124 adapted to receive a PDP bearer eventdetection report carrying signaling PCC rule names, and send a signalingIP flow path status report to the AF.

According to yet another embodiment of the invention, there is provideda PCRF with configuration as structured in FIGS. 11 and 12.

Apparently, various modifications and variations can be made to theinvention without departing from the spirit and scope of the inventionby those skilled in the art, and therefore the invention is intended toencompass all these modifications and variations provided that they fallwithin the scope of the claims appended to the invention and theirequivalents.

1. A method for reporting a bearer event of a signaling IP flow,comprising: generating, by a processor of an apparatus operable toprovide an Application Function, flow identifier information of asignaling IP flow; sending, by the apparatus operable to provide anApplication Function, a subscription request for subscribing to a bearerevent of the signaling IP flow to an apparatus operable to providePolicy Control and Charging Rules Function, wherein the subscriptionrequest carries the flow identifier information of the signaling IPflow; and receiving, by the apparatus operable to provide an ApplicationFunction, a bearer event report of the signaling IP flow generated by aprocessor of the apparatus operable to provide Policy Control andCharging Rules Function, wherein the bearer event report carries theflow identifier information of the signaling IP flow, wherein the flowidentifier information comprises a media component number and an IP flownumber, and the signaling IP flow is provided with a default mediacomponent number
 0. 2. The method according to claim 1, furthercomprising: establishing, by the apparatus operable to provide PolicyControl and Charging Rules Function, Policy Control and Charging rulesand Policy Control and Charging rule names corresponding to thesignaling IP flow in accordance with the flow identifier information ofthe signaling IP flow, and sending the Policy Control and Charging rulesand the Policy Control and Charging rule names to an apparatus operableto provide Policy and Charging Enforcement Function; reporting, by theapparatus operable to provide Policy and Charging Enforcement Function,upon detection of the bearer event subscribed to by the apparatusoperable to provide Policy Control and Charging Rules Function, thePolicy Control and Charging rule names associated with the bearer eventand the detected bearer event to the apparatus operable to providePolicy Control and Charging Rules Function; and generating, by aprocessor of the apparatus operable to provide Policy Control andCharging Rules Function, the bearer event report carrying informationincluding the flow identifier information of the signaling IP flowcorresponding to the Policy Control and Charging rule names associatedwith the bearer event.
 3. The method according to claim 2, furthercomprising: establishing, by the apparatus operable to provide PolicyControl and Charging Rules Function, upon receiving the subscriptionrequest, the Policy Control and Charging rules and the Policy Controland Charging rule names corresponding to the signaling IP flow inaccordance with the flow identifier information of the signaling IPflow, after determining whether a Policy Control and Charging rule or aPolicy Control and Charging rule name is available for the signaling IPflow.
 4. The method according to claim 1, further comprising: sending,by the apparatus operable to provide Policy Control and Charging RulesFunction, if the apparatus operable to provide Policy Control andCharging Rules Function determines that the Policy Control and Chargingrules and Policy Control and Charging rule names are available for thesignaling IP flow in accordance with the flow identifier information ofthe signaling IP flow, the Policy Control and Charging rules and thePolicy Control and Charging rule names to an apparatus operable toprovide Policy and Charging Enforcement Function; reporting, by theapparatus for providing Policy and Charging Enforcement Function, upondetection of the bearer event subscribed to by the apparatus forproviding Policy Control and Charging Rules Function, the Policy Controland Charging rule names associated with the bearer event and thedetected bearer event to the apparatus for providing Policy Control andCharging Rules Function; and generating, by a processor of the apparatusoperable to provide Policy Control and Charging Rules Function, thebearer event report carrying information including the flow identifierinformation of the signaling IP flow corresponding to the Policy Controland Charging rule names associated with the bearer event.
 5. Anapparatus operable to provide an Application Function, comprising: afirst subscription request sending unit adapted to send a subscriptionrequest for subscribing to a bearer event of a signaling IP flow to anapparatus operable to provide Policy Control and Charging RulesFunction, wherein the subscription request is generated by a processorand carries a generated flow identifier information of the signaling IPflow; and a first bearer event report receiving unit adapted to receivea bearer event report of the signaling IP flow from the apparatusoperable to provide Policy Control and Charging Rules Function, wherethe bearer event report carries the flow identifier information of thesignaling IP flow; wherein the flow identifier information comprises amedia component number and an IP flow number, and the signaling IP flowis provided with a default media component number 0.